Acoustically, there will not be a better location than under the drivers dash.
So in order to maintain good leg room what are the largest enclosure dimensions that will fit in the above location?

David

Can't remember my measurements but i believe much more than 6" into the foot area and it would start to be in the way. Also not alot of height either. I figured a 10" would be as big as i would probably go.

Would it be possible to use a free air sub and put it in the walkway somewhere?